A catholicate or catholicosate is the area of responsibility (territorial or otherwise) of a catholicos, a leader within any of the several churches of Eastern Christianity, especially those regarded as Oriental Orthodoxy. The word is derived from the Greek Καθολικος, meaning "wholeness."
While a catholicos is sometimes considered to correspond to a bishop in the Roman Catholic and Protestant traditions, a catholicate is typically a larger and more significant organizational division than a bishopric, archdiocese or episcopal see. Catholicates often have distinct cultural traditions established over many centuries.
Within the Armenian Apostolic Church there are two catholicosates: the Mother See of Holy Etchmiadzin in Etchmiadzin, Armenia, and the Catholicosate of the Great House of Cilicia in Antelias, Lebanon. In the 10th century, when lands inhabited by Armenians were devastated by Seljuks, the Armenian church took refuge in Cilicia. In the 15th century, a new catholicos was elected in Etchmiadzin.
While some traditions favor the English language spelling "catholicate", others favor "catholicosate." There is a degree of inconsistency in this regard. Others spellings, including "catholicossate", are seen as well.